680. Tocopherols. Part V. Structural studies on ε- and ζ-tocopherol

Abstract

Natural c-tocopherol has been shown to differ from synthetic 5methyltocol, with which it had previously been identified. Spectroscopical, chromatographical, synthetical, and degradative evidence is presented confirming the nature of the synthetic compound. &-Tocopherol would appear to be a 5,8-disubstituted chromanol, related to the tocols, but perhaps with altered substitution at C(2). Natural c-tocopherol from wheat bran is not identical with 5,7-dimethyltocol, which structure had been given it, but appears to be the trisubstituted representative in the same series as E-tocopherol. The <-tocopherol that occurs in rice, however, is apparently identical with authentic 5,7-dimethyltocol.WHEN McHale, Mamalis, Marcinkiewicz, and Green's synthetic 5-methyltocol l was converted into a nitroso-derivative by Quaife's method and this compound compared chromatographically with the nitroso-derivative of natural E-tocopherol the Rf values of the two compounds were different. Since c-tocopherol has been identified with 5methyltocol, it was necessary to compare in detail the chemistry of the two compounds.Eggitt and Ward considered that &-tocopherol was 5-methyltocol because, on partition chromatography (a system sensitive to molecular-weight differences) , it migrated almost identically with 8-methyltocol. This was also the view of Green, Marcinkiewicz, and Watt: who found that the substance migrated in a two-dimensional adsorption-partition chromatographic system to the same position as 7-methyltocol. Eggitt and Nonis 6 compared the behaviour of E-tocopherol with that of other tocopherols and concluded that &-tocopherol was probably 5-methyltocol, from the failure of the former to enter coupling reactions, its formation of a nitroso-derivative whose ultraviolet and visible spectra were closely similar to those of the nitroso-derivative of 5,8-dimethyltocol, the nearly Part IV, preceding paper.

Über die Chemie des Vitamins E. 8. Mitteilung [1]. Die Stereochemie von natürlichem γ‐Tocotrienol (Plastochromanol‐3), Plastochromanol‐8 und Plastochromanol‐8

“…Zur Isolierung und Reindarstellung wurden vor allem Palmol [4] und Latex von Hevea brasiliensis (Gummibaum) [6] [7], in welchen interessanterweise alle vier Tocotrienole bzw. a-, p-, und d-T-3 nebeneinander vorkommen, sowie Weizenkleie (a-und j3-T-3) [8] [9] und Reis (a-und y-T-3) [4] als naturliche Quellen herangezogen.…”

“…all-trans-und cis-trans-y-Tocotrienol 1. 2, (1):M-C5Hs-C5H8;257 (3,5); 229 (4) ; 215 ( 2 ) ; 203 (7) : M -C5H,-2 (C5H,) ; 189 (83,5) C12H1302; 175 (4,5) ; 161 (3,5) ; 151 (23,5) ; 135 (7) ; 121 (8,5) ; 107 (7) The stereochemistry of y-tocotrienol (plastochromanol-3) from latex of Hevea brasiliensis (rubber tree), plastochromanol-8 from leaves of Hevea brasiliensis, and plastochromenol-8 from tobacco is reported.…”

Weathering and biodegradation of hydrothermal petroleum in the north rift of Guaymas Basin, Gulf of California

“…Figure 3e). α-Tocopherol (vitamin E) is an antioxidant in the lipids of all higher organisms and is oxidized in the depositional environment to the lactone derivative (VIII) (Green et al, 1959).…”

The isolation and properties of δ-tocotrienol from Hevea latex

“…A small sample of 8-tocotrienol was hydroxymethylated according to the method of Green, McHale, Marcinkiewicz, Mamalis & Watt (1959). The method involved warming the tocotrienol with potassium hydroxide and 40% (v/v) formaldehyde in ethanol in a sealed capsule for 1 hr.…”

“…The ,B-tocotrienol was isolated by preparative thinlayer chromatography and its identity was checked by colour reactions and chromatography. Green et al (1959) found that 8-tocopherol could be hydroxymethylated and reduced to yield ,B-tocopherol. DISCUSSION 8-Tocotrienol has been isolated from a preparation of latex from Hevea bra8ilien8i8 and chemical and physical investigations have confirmed its structure.…”